Breech mechanism for a rifle



June 11, 1957 A. F. GAIE-JOS 2,

'BREECH MECHANISM FOR A RIFLE Filed Dec. 8, 1952 2 Sheets-Sheet l E 3 ifammo v Alunzn E Euidus June 11, 1957 A. F. GAlDOS BREECH MECHANISM FOR ARIFLE 2 Sheets-Sheet 2 Filed Dec. 8, 1952 gvwvwim Alunzu F. Euidds 7WW+d M United States Original application February 1, 1950, Serial No.141,8(21. Divided and this application December 8, 1952, Serial No.324,856

2 Claims. (Cl. 89-187) (Granted under Title 35, U. S- Code (195]), sec.266) The invention described herein may be manufactured and used by orfor the Government for governmental purposes without the payment of anyroyalty thereon.

This invention relates to an improvement in a breech mechanism for arifle and more particularly to the type of rifle as shown in mycopending application, Serial No. 141,801, filed February 1, 1950, andnow matured into U. S. Patent No. 2,688,203, of which this applicationis a division.

An object of this invention is the provision in a firearm of an improvedbreech lock adapted to unlock in direct response to the forward movementof a longitudinally reciprocable member.

It is a further object of this invention to provide improved means foractuating a breech lock of the type which is slidably disposed in thereceiver at an acute angle to the vertical axis thereof.

Another object of this invention is to provide a direct manual means ofunlocking the lock prior to handcharging the firearm.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown in the accompanying drawings in which:

Fig. 1 is a fragmentary longitudinal cross-sectional right side viewshowing the breech lock in the locked position;

Fig. 2 is a fragmentary longitudinal cross-sectional right side viewshowing the lock in the unlocked position during manual operation of theactuator;

Fig. 3 is a cross-sectional view taken on lines 33 of Fig. 2;

Fig. 4 is a fragmentary perspective view of the actuator bar;

Fig. 5 is a cross-sectional view taken on lines 55 of Fig. 1;

Fig. 6 is a fragmentary perspective view of the rear end of the bolt;and

Fig. 7 is a perspective view of the firing pin retainer.

The particular embodiment of the invention chosen for the purpose ofillustration, as shown in the drawings, comprises a receiver 12, a boltassembly 13, a breech lock 14 and an actuating bar 15.

Receiver 12 is provided with a longitudinal bore 16 in the upper forwardpart thereof to receive bolt assembly 13. Receiver 12 has a downwardlydepending rectangular portion 17 being provided with a vertical magazineopening 18 to receive a magazine 19. Portion 17 is also provided with anangular slot 20 to receive lock 14 which will be described later.

On the forward upper right side of receiver 12, angularly disposed abovethe axis, there is a longitudinal slot 30 provided to permit ejection ofa fired round and for the accommodation of a bolt handle 31. On the rearsurfaces of portion 17 of receiver 12 a transverse slot 37 is providedto receive a retainer 38 of a bolt return spring rod 39. A helicalspring 41 surrounds bolt return spring rod 39 for a purpose to be laterdescribed.

atent Bolt assembly 13 comprises a bolt 21 cylindrical in contour havinga firing pin tunnel 22 therein to receive a firing pin 23 of aconventional shape and such bolt is reciprocable in bore 16. A firingpin spring 24 surrounds pin 23 thereby biasing such pin rearwardly.Bolt-21 is provided on the rear end thereof with vertically positionedways 25 to receive a firing pin retainer 26. Firing pin 23 has a reduceddiametrical portion 27 on the rear end thereof which is slidablyreceived in hole 28 of retainer 26. Bolt 21 is provided with atransverse slot 29 on the bottom near the rear end thereof to receivelock 14. Bolt 21 is provided with a longitudinally dove-tailed slot 32on the forward right side angularly disposed above the horizontal axisthereof to receive bolt handle 31.

Retainer 26 is provided with a rectangular open slot 33 on the bottomend thereof to clear and permit a bolt return slide 34 to contact bolt21. Bolt return slide 34 is provided with a depending body portion 35having a longitudinal axial hole 36 therein. Bolt return slide 34 isslidably mounted on return spring rod 39 by means of hole 36. Boltreturn slide 34 is biased forwardly by spring 41, thereby urging bolt 21into the battery position.

Receiver 12 is provided with oppositely disposed longitudinal ways 40 onthe left side thereof juxtaposed to slot 20 to slidably receiveactuating bar 15 for reciprocating movement therein. Actuating bar 15 isprovided with oppositely disposed ribs 44 that are receivable in ways 40of receiver 12. Actuating bar 15 is provided with a lock actuating stud43 protruding from the right side thereof. Look 14 is provided with anangularly disposed slot 42 on the left side thereof arranged to slidablyreceive stud 43 of actuating bar 15. Oppositely disposed from stud 43,actuating bar 15 is provided with an arm 46 for manually operating lock14 for a purpose to be described, An elongated slot 50 is provided onthe left side of receiver 12 to permit movements of arm 46 therealong.Actuating bar 15 is spring-biased rearwardly by spring means (not shown)thereby camming the lock upwardly and locking the bolt in the batteryposition and such bar is actuated forwardly by gas pressure accumulatingin an actuating cup (not shown) thereby camming the lock downwardly andunlocking the bolt from the battery position.

Operati ns After the insertion of magazine 19, loaded with a double rowof cartridges 47, into the magazine opening 18 of receiver 12 andsecured therein by a magazine latch 43, lock 14 then is carnmeddownwardly out of slot 29 of bolt 21 by pressing forwardly on arm 46with the thumb of the left hand, such arm being on the left side of therifle. The bolt 13 is then retracted to the rear by handle 31 permittingthe uppermost cartridge 47 in the magazine 19 to enter the chamberingspace between the bolt 13 and the end of a barrel 49 whereby on thereturn of the bolt to the battery position, the round is chambered inthe barrel and the gun is charged for firing. After discharge of thecartridge 47 and when a conventional bullet has cleared the bore at themuzzle end (not shown) and while passing through the actuating cup (alsonot shown) the gases in escaping from such bore impinge upon the innerwall of such cup that is coupled with the actuating bar 15 which in turnmoves such bar forwardly thereby camming the lock 14 downwardly.

It will therefore be apparent to one skilled in the art that applicationof the principle of the invention disclosed herein provides novel andimproved firearm construction which is outstandingly characterized by asmall number of parts with simplicity of configuration by such parts andalso in cheapness of manufacture.

I claim:

1- In a recoil operated firearm having a fixed barrel Patented June 11,1957.

and a longitudinally reciprocal bolt, an angularly disposed bolt lockslidable into' and outofvcrtical locking engage ment with the undersideof the bolt, said lock having a forwardly and upwardly inclined cam.slot. formed along one. side thereof,,a bolt lock aetuator slidablymounted below the bolt for reciprocal movementpara-llel thereto, and astud projecting transversely from thepsideof said actuator to engage insaid slot in said. bolt lock i for camming said lock. downwardlyandrearwardly' out of locking engagement with the bolt during forwardmovement of said actuator.

2;,In a recoil operated firearm having a receiver, a

b'arrelfixedly secured thereto, and a bolt'slidably mounted said slot insaid bolt lock for camming said lock downwardly and rearwardly out oflocking engagement with during the conclusion of battery movement.

References lflitedinthe file of this patent UN ITED- STATES PATENTS1,363,696 Thompson Dec. 28, 1920 1,363,809 Payne Dec. 28, 1920 1,397,698Payne Nov. 22, 1921 1,410,270 Pedersen- Mar. 21, 1922 1,489,989 DiehmApr. 8, 1924 2,135,005 Hoagland ,et a1. Nov. 1, 1938 2,527,895 IassanOct. 31, 1950 FOREIGN PATENTS 593,045 Germany Feb. 20, 1934 609,900Germany Feb. 26, 1935 572,927 Great Britain Oct. 30, 1945

